Re: Growth spurt or not enough milk?
It's almost certainly just normal infant behavior. Many babies are born somewhat sleepy, and will go as long as 3-4 hours between nursing sessions, sometimes even longer! This actually isn't ideal- a newborn who is routinely going 3-4 hours between feedings should be woken to nurse every 2-3 hours during the day, in order to ensure that the baby gets enough milk. As time goes on and babies become more alert, most of them start to adopt a pattern of more frequent feedings. Nursing every 1-2 hours is totally normal, and in no way an indication of supply problems.
You should suspect supply problems only if your baby produces less than the minimum number of wet and poopy diapers in a 24 hour period, or is not growing or developing at a normal pace.
Coolest thing my big girl said recently: "How can you tell the world is moving when you are standing on it?"
Coolest thing my little girl sang recently: "I love dat one-two pupples!"